This invention relates to vertical swinging-blade water wheels capable of converting a kinetic energy of a substantially horizontal stream into mechanical rotational energy.
These types of vertical swinging-blade water wheels are well-known in the art. For example, an apparatus as illustrated in Japanese Patent Specification No. 32365/75 comprises a fixed circular horizontal base plate to act as a weight, a supporting frame attached to the top of the base plate, bearings disposed at the center of the top of the frame and the base plate center opposite thereto respectively, a vertical blade wheel shaft born by such bearings and extending upward through the upper bearing, upper and lower horizontal arms with the same length extending radially from the water wheel shaft at equiangular spaces within the supporting frame, auxiliary shafts connecting the outer ends of the upper and lower arms, swinging blades pivotably attached to the auxiliary shafts, and vertical stop pins disposed on the lower arms at positions away from the auxiliary shafts over a distance a little shorter than the blade width. When the swinging-blade water wheels are sunk at the bottom of a water flowing in the horizontal direction, the blades resting on the pins are thrusted by the stream in the flowing direction. The blades located in positions symmetrical to such blades with respect to the water wheel shaft are not subject to the stream pressure as they are in free positions away from the stop pins. Thus, the vertical water wheel shaft is rotated around the axis by the blades subject to such stream pressure, thereby supplying mechanical power output to an optional apparatus via the upper end of the shaft.
However, such type of swinging-blade water wheel suffered from a major defect that it requires either larger area of blade or greater number of blades in order to obtain an intensive power output efficiently from a relatively slow stream. The former requirement will result in too expensive initial cost, while the later will bring about interference among the blades, causing decreased efficiency. Further, such apparatus also has a defect that the water wheel as a whole rotates about itself, thereby entangling the mooring cable, so that it may not be used in a floating state.